// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_DOWNLOAD_DRAG_DOWNLOAD_FILE_H_
#define CONTENT_BROWSER_DOWNLOAD_DRAG_DOWNLOAD_FILE_H_

#include <memory>

#include "base/compiler_specific.h"
#include "base/files/file.h"
#include "base/files/file_path.h"
#include "base/macros.h"
#include "base/memory/ref_counted.h"
#include "base/memory/weak_ptr.h"
#include "base/run_loop.h"
#include "base/single_thread_task_runner.h"
#include "content/browser/download/download_file.h"
#include "content/common/content_export.h"
#include "content/public/browser/download_item.h"
#include "content/public/browser/download_manager.h"
#include "content/public/common/referrer.h"
#include "ui/base/dragdrop/download_file_interface.h"
#include "url/gurl.h"

namespace content {

class WebContents;

// This class implements downloading a file via dragging virtual files out of
// the browser:
// http://lists.whatwg.org/htdig.cgi/whatwg-whatwg.org/2009-August/022118.html
// http://www.html5rocks.com/en/tutorials/casestudies/box_dnd_download/
class CONTENT_EXPORT DragDownloadFile : public ui::DownloadFileProvider {
public:
    // On Windows, we need to download into a temporary file. On posix, we need to
    // download into a file that has already been created, so only the UI
    // thread is involved. |file| must be null on windows but non-null on
    // posix systems. |file_path| is an absolute path on all systems.
    DragDownloadFile(const base::FilePath& file_path,
        base::File file,
        const GURL& url,
        const Referrer& referrer,
        const std::string& referrer_encoding,
        WebContents* web_contents);

    // DownloadFileProvider methods.
    void Start(ui::DownloadFileObserver* observer) override;
    bool Wait() override;
    void Stop() override;

private:
    class DragDownloadFileUI;
    enum State { INITIALIZED,
        STARTED,
        SUCCESS,
        FAILURE };

    ~DragDownloadFile() override;

    void DownloadCompleted(bool is_successful);
    void CheckThread();

    base::FilePath file_path_;
    base::File file_;
    const scoped_refptr<base::SingleThreadTaskRunner> drag_task_runner_;
    State state_;
    scoped_refptr<ui::DownloadFileObserver> observer_;
    base::RunLoop nested_loop_;
    DragDownloadFileUI* drag_ui_;
    base::WeakPtrFactory<DragDownloadFile> weak_ptr_factory_;

    DISALLOW_COPY_AND_ASSIGN(DragDownloadFile);
};

} // namespace content

#endif // CONTENT_BROWSER_DOWNLOAD_DRAG_DOWNLOAD_FILE_H_
